The non-volant mammals of the Estacíon Biológica Allpahuayo: Assessment of the natural history and community ecology of a proposed reserve

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Abstract

South American mammals have received increasing attention in recent years in part due to their high species diversity, functional complexity at the level of communities, and endangerment as a result of anthropogenic activities. These activities include deforestation and habitat alteration, the 2 major threats to biodiversity in the Neotropics. Indeed, many habitats are lost before basic inventories of plant and animal communities can be compiled. In addition, basic natural history information is lacking for many, if not most, neotropical species, especially in the Amazon Basin. Such basic information is essential for natural resource management and conservation to be successful.
To obtain such information at one site, the small mammal community at the Estacion Biologica Allpahuayo in northeastern Peru was monitored for 18-months. Data were collected to describe and quantify small mammal communities in pristine habitats and document the impacts of disturbance on these communities. These data represent one of the most comprehensive data sets on mammals ever collected from one site in Amazonia.
A total of 37 species of marsupials (13) and rodents (24) were documented at the site, which represents one of the most species-rich communities reported from the Neotropics. Estimates of local species richness indicate that the small mammal community was sampled approximately 90% completely, but that only 64% of species that occur in the region were documented. Communities in forested habitat were more rich and diverse than those present in secondary growth and communities in older secondary growth were more diverse than those in more recently disturbed habitats. Community composition also changed significantly among different aged habitats, with unique species present in both disturbed and undisturbed habitats. Those present in disturbed areas tended to be habitat generalists whereas those in forest wore habitat specialists. One encouraging result was that the mammal community in 15-year-old disturbed habitat was equally diverse and similar in community composition to that present in mature forest. This suggests that small mammal communities can recover from disturbance events in a relatively short period of time, if the area remains fallow during the recovery period and is adjacent to mature forest. The latter of these is important for facilitating dispersal of forest species into these areas. The structure of the dominance hierarchy of communities did not change in different habitat types. However, different species were dominant in different habitats, with Philander opossum and Proechimys brevicauda dominant in disturbed areas and Proechimys cuvieri and Oryzomys perenensis dominant in mature forest.
To maintain the high number of species present at EBA, large tracts of rain forest must be preserved intact. The biggest source of habitat disturbance and fragmentation in the Iquitos area is anthropogenic in origin, particularly subsistence farming. Whereas a low level of this type of disturbance increases mammalian diversity by providing a mosaic of disturbed and undisturbed habitats across the landscape, too much disturbance will upset that balance and diversity will begin to decline as forested habitats become isolated. Educating the local people about the importance of conserving the rain forest needs to be a priority if it is to be preserved in the Iquitos region. Methods that lessen their impact on rain forest resources, but are profitable, need to be developed and implemented. However, it is difficult to preserve what is not understood. Studies such as this increase our understanding of the ecology of one aspect of the rain forest biome. This, coupled with other studies in other areas of biology, lays the foundation for understanding and thus, preserving this magnificent biome.